1. Field of the Invention
The present invention relates to a machine translation system and, more particularly, to a machine translation system which can obtain a translated sentence in which translated words corresponding to a given original word are consistent.
2. Description of the Related Art
In recent years, a machine translation system as a system for automatically translating an input original text by utilizing a computer has been receiving a great deal of attention. Basically, the machine translation system performs morphological analysis and/or syntactic analysis of an input original text to divide the text into predetermined translation processing units such as words or phrases, and retrieves a translation dictionary for each translation processing unit to obtain a corresponding translated word. The system then links the translated words corresponding to the translation processing units in accordance with a predetermined translation rule to generate translated sentences. In this manner, a translated text corresponding to the original text is obtained.
The major characteristic feature of the machine translation system is that a translated text consisting of translated sentences using the same translated word corresponding to the same word or phrase in an original text can be obtained upon retrieval of a translation dictionary. For example, assume that a Japanese translated text is to be obtained based on an English original text. In this case, if a translated word "konpyuuta (although a Japanese is expressed (written) in kanji characters (Chinese characters) as ideographic characters, hiragana and katakana characters as phonetic characters, or their combinations, a method of expressing pronunciations of Japanese using Roman letters is used herein)" for a word "computer" and a translated word "konpyuuta-nettowaaku" for a word (or phrase) "computer network" are registered in a translation dictionary, translated words "konpyuuta" and "konpyuuta-nettowaaku" are respectively used for the words (phrase) "computer" and "computer network" to generate a translated text. This is one of great advantages of the machine translation system in consideration of the fact that when an original text is manually translated without using the machine translation system, in particular, when one original text is partially translated by a plurality of persons, it is not easy to obtain a translated text in which translated words of the same words (phrases) are consistent.
However, assume that a translated word "keisanki-aakitekucha" is registered for a word (phrase) "computer architecture". In this case, if an original sentence includes a word (phrase) "computer network", although a translated word of the word "computer" in this case must be a translated word "konpyuuta" in "konpyuuta-nettowaaku", the translated word of "computer" in this case must also be a translated word "keisanki" in "keisanki-aakitekucha" if there is a phrase "computer architecture" in an original text. That is, there are different translated words "konpyuuta" and "keisanki" for the same word "computer" in a translated sentence. Therefore, in this case, the advantage of the machine translation system is considerably impaired. In this case, if a translated word "konpyuuta-aakitekucha" is registered for "computer architecture", a given translated word "konpyuuta" can always be obtained for a word "computer". However, even when translated words are registered in the translation dictionary in advance so as to obtain the same translated word for the same original word, if a user changes a translated word of "computer architecture" from "konpyuuta-aakitekucha" to "keisanki-aakitekucha" or registers a new translated word of "keisanki-aakitekucha", the word "computer" then has different translated words "konpyuuta" and "keisanki". In this manner, in an existing system, the advantage of the machine translation system in that a translated sentence with consistent translated words can be obtained is considerably impaired when translated words are changed or new ones are registered.
In this manner, in the existing machine translation system, when translated words are changed or new ones are registered, translated sentences in which translated words are not consistent for the same words (phrases) in an original text are undesirably generated.